The present invention relates to an ink ejection method and an ink ejection device employing the ink ejection method.
In the inkjet printer, an extra ink droplet called a satellite droplet may be generated in addition to a main ink droplet. When a plurality of droplets are continuously ejected to form a dot, and thereafter, if the pressure wave vibration in a pressure chamber is not reduced sufficiently, such a residual pressure wave vibration will cause an extra ink droplet to be ejected in the form of a satellite. Further, although the satellite ink droplet is not generated, formation of a succeeding ink dot may become unstable due to the variation of the pressure wave in the pressure chamber. Conventionally, in order to deal with such a phenomenon, a cancel pulse is inserted in the drive waveform to suppress the vibration in the pressure chamber.
U.S. Pat. No. 6,663,208 B2 discloses a controller for inkjet apparatus, which controller controls outputting of drive waveform to suppress the vibration in the pressure chamber, the teachings of which being incorporated herein by reference.
FIG. 13 shows a timing chart that is similar to FIG. 7 of the U.S. Pat. No. 6,663,208 B2. The timing chart shows four waveforms: a drive waveform #0; a drive waveform #1, a drive waveform #2, a drive waveform #3, and a long waveform selection signal. The sections indicated by A-D are print cycles, respectively. Drive waveform #1 is used to output a plurality of pulses within a print cycle to form a single dot. Drive waveforms #2 and #3 are used to output a plurality of pulses over two adjacent print cycles. Drive waveforms #2 and #3 have a plurality of ejection pulses that cause continuous ejection of a plurality of ink droplets, and a cancel pulse at the end that suppresses the pressure wave vibration in the cavity. The drive waveforms #2 and #3 have the same pulse string but are shifted from each other by one print cycle, which is defined by a strobe signal.